Antec True550 won't power my system??

[Posidon42]

Alright this is really messed up. Help me figure out what is going wrong. For the last month, I have been doing some overclocking and folding with my mobile Barton 2500+. While fairly pleased with the result (200x12@1.85V), I wanted more. But all attempts at getting a higher clock out of the cpu resulted in failure. But since I was using a decent watercooling setup (mag5, maze4 amd, caprice core with 2x 120mm enermax aluminum fans) I thought there were other parts of my system holding it back.

The only thing I could think of was the power supply. Originally, I had it running a 350W Enermax POS that could only run the cpu up to 2.2ghz. A couple weeks ago I bought a 350W Sparkle off one of the forum members and got it up to the 2.4ghz it is running at right now. Pretty good so far, and I was fairly happy.

However, when perusing the forums one day, I came across a nice deal on a used Antec True550 power supply. I bought it and today is the first time I have attempted to use it. So far, I am not impressed, but I don't know what is wrong.

I reset the bios and powered on the system. Everything seemed ok. I changed all the pertinent settings for the cpu but I wanted to keep the steps small. So I set it to 200x10 @ 1.7V. This used to be a perfectly stable settting and both of the other power supplies handled it perfectly fine. But this one won't. As soon as the computer tries to boot, it powers on the fans for a second and then everything completely shuts off. Then the power supply starts emitting this two tone warbling sound. :mad:

WTF is going on?? This ANTEC can't hack what every other power supply I have ever had can?? I am very dissappointed right now, so I hope some of you can help me figure out what is going on.

By the way, here is what I am running:
AMD mobile barton 2500+
NF-7 (non-s) v2.0
GF3Ti500 video card
512mb Kingston HyperX pc2700 (the memory runs fine at 200mhz, I just have to turn the speeds down to 3-3-3-8 :( )

[shortyes]

yeah I had some problems with the antec true power. First off let me ask something

does the beep sound like de du de du de du de du or .... a siren

If it does then there is either a heating problem aka overheating cpu, HSF is not seated properly, or there is a voltage error from the PSU.

1) Install any of the other 2 PSU and see if the board powers up if not then there is a overheating. If it powers up then the antec is out of spec

2) reseat the HSF and then try it, if the siren is still going then the mobo is dead and you need to RMA it

I had to RMA my boards because something was wrong with it

[Posidon42]

I don't think any of those will help me. I can reset the CMOS and it will boot again. But as soon as I start overclocking it, the psu starts beeping.

Yes, the description you gave sounds like what it is doing.

The system hasn't been running so I know it isn't overheating and I just put the water block back on this afternoon. I know it isn't overheating on the block because I put a secondary thermal monitor about a mm from the cpu die on the block. This is being read by my digidoc and it says 25c when the bios says 32c. Close enough, but by no means overheating temperatures.

[Posidon42]

I decided to switch out power supplies back to the one that used to work and now it is doing the same thing! I also found out that the noise isn't coming from the power supply, it is coming from the speaker on the motherboard. The only thing I did yesterday, other than swapping out power supplies, was to remove the northbridge cooler and replace it with a nice old celeron heat sink.

Is it possible this is the problem? The heatsink is extruded aluminum that I lapped to 1500 grit and then put ceramique between the nb and the hs. The hs is attached to the mobo via some small bolts I found which are electrically isolated from the back of the case via some double sided adhesive mounting pads. Hopefully this will help someone figure out the problem.

[Posidon42]

heh, it turns out that the northbridge was the problem. When I put that new heatsink on it, I plugged the new fan into the normal fan header and not into the fan header for the northbridge. Well it turns out that the motherboard really wants a fan signal on those pins. As soon as I plugged that fan back in, it is back to working perfectly fine. Thanks for all the help people.

Maybe we can add this to the "make sure you do this if you are modding" list somewhere?